This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. BioCARS is offering a series of crystal screening sessions, where local user groups are able to evaluate new crystals at short notice. An important part of crystal growth and optimization is evaluating crystal quality and new crystal forms. This process is usually painstakingly done on a rotating anode at the home institution. We propose to do this screening at the APS because of the increased beam intensity and quality of synchrotron radiation. Besides greatly speeding up the process, diffraction images obtained at the APS should give a better indication of crystal quality. Our previous clinics have proven very popular and useful to local users. We are only offering these screening sessions to registered APS users with current training, so some of the data collected under this proposal could also be associated with other general user proposals. Absolutely no hazardous samples or materials will be allowed given the collection of different user groups and short notice for addition of new samples and personnel.